Device for circulating grain products

ABSTRACT

A device for circulating a grain product includes feed screw for the grain product and a connected drive unit for driving the feed screw. The drive unit is non-rotatably connected with a support body with a lower support surface which is inclined relative to the axis of the feed screw. The support body includes a surface area capable of withstanding the transport capacity of the feed screw. The support body further includes at least one blocking plate immersed in the grain product, wherein the surface area of the blocking plate is sized to withstand the peripheral forces generated by the rotating feed screw.

This is an application filed under 35 USC 371 based onPCT/DE2004/000387.

BACKGROUND OF THE INVENTION

The invention relates to a device for circulating a grain product.Devices of this type are used in the grain processing industry, inparticular for drying and/or storing a grain product.

The moisture content of freshly harvested grain does not permit storagewithout the risk of spoilage. The moist grain forms hotspots whichincrease in size and ruin the grain. In addition, insects settle atthese locations and contribute to the damage of the grain product.

For this reason, freshly harvested grain must be adequately dried beforebeing stored, which is typically done in drying silos. The freshlyharvested grain is continuously or cyclically fed into the drying silofrom the top, while dry, warm air is blown into the drying silo frombelow. The dry air removes a certain amount of water from the grain andis vented into the ambient air from the upper region of the drying silo.The drying process can be accelerated by continuously circulating andintermixing the grain product. It is known in the art to employ acirculating unit located and operating in the upper region of the dryingsilo. This circulating unit is provided with a several driven feedscrews arranged side-by-side, which are immersed in the deposited grainproduct and circulate the grain product from the bottom to the top. Thefeed screws reach all areas of the deposited grain product due to therevolving motion of the circulating unit and the changing radialposition of the individual feed screws.

After an adequate drying process, the grain product is moved for storageinto corresponding round storage silos or into low-rise storagebuildings, where the grain product must be continuously aerated and/orcirculated. This process is intended to prevent a formation of hotspots.

For example, DE-OS 27 21 782A discloses a correspondingcirculation-storage unit for grain products for use in a round storagesilo. This circulation-storage unit for the grain product is located inthe center of the storage silo, is fixedly connected with the storagesilo, and includes essentially a conveyor cylinder and a driven feedscrew. The stored grain product slides across a conical bottom into theregion of the feed screw and is transported by the feed screw throughthe conveyor cylinder into the upper region of the storage silo, whereit is once more deposited on the already deposited grain product. Thisproduces a revolving feed motion.

The circulation-storage unit for grain products is implemented as afixed component of the storage silo and is therefore provided only forthis particular application. The unit cannot be used in low-rise storagebuildings because of its restricted effective range, which severelylimits in the application of the circulation-storage unit. The costsassociated with designing and manufacturing the circulation-storage unitfor grain products is also quite high because it requires a conveyorcylinder.

After drying, the grain product is typically transported to largestorage buildings, where it is poured out to form a flat pile. The grainis typically circulated by turning it over manually, which requires alot of manual labor and many workers. It is also known in the art to useheavy mixing machinery for circulating the grain, which is not alwaysavailable and is in addition very expensive. DE 35 00 881 A1 discloses adrilling screw for turning and loosening grain in storage fillingspaces, which essentially consists of a hand drill and a feed screwclamped in the hand drill. The feed screw has a length corresponding tothe height of the poured grain. The drilling screw is supported by thebottom of the silo by a sphere disposed on the tip of the feed screw.The drilling screw can be used both in round storage silos and inlow-rise storage buildings. However, the drilling screw is relativelyineffective in low-rise storage buildings. Significant manual forceshave to be generated to overcome the resistance of the drilling screwrotating in the grain, to hold the drilling screw in its operatingposition during operation and to move it from place to place. Thedrilling screws can therefore be operated only for short periods oftime, which essentially prevents their use in low-rise storagebuildings.

U.S. Pat. No. 4,491,422 discloses a similar device for circulating agrain product from a lower to an upper storage region. The device has asimilar design, but includes an additional braking plate which opposesthe inertial and feed forces and thus prevents the device from beingimmersed in the grain product.

U.S. Pat. No. 5,980,100 describes a device for treatment of a fluid,such as mixing or aerating of waste water. This device includes a feedscrew and a drive unit for the feed screw. The drive unit and the feedscrew are coupled to one another by a coupling unit. This device isintended for swirling the waste water in the region of the feed screwand, in a particular embodiment, introduces air at atmospheric pressurethrough a pipe into the water.

It is therefore an object of the invention to develop a device of thistype for circulating a grain product, which can be used over anunlimited period of time and which does not require a manual force forcirculation.

BRIEF SUMMARY OR THE INVENTION

The object is solved by providing a device for circulating a grainproduct from a lower to an upper storage region, in which the feed screwhas a length greater than the immersion depth of the blocking plate andthe feed screw is sized so as to enable the grain product to becirculated from a lowermost to an uppermost storage region. Further,advantageous embodiments of the device include a support body beingcup-shaped with a support surface of arbitrary shape and an open sidefacing away from the feed screw or facing towards the feed screw. Thesupport body may also be provided with a filling space for the conveyedgrain product and the filling space may include a lateral dischargeregion for depositing the conveyed grain product onto the grain pile,wherein the dimensions of the filling space and the dimensions of thedischarge region are matched to one another, so that a pressuresufficient to move the drive is generated by the conveyed grain productand applied to the device inside the filling space. For regulating thedrive velocity of the device, the filling space includes near itsdischarge region an adjusting device, which adjusts a cross-section ofan opening of the discharge region in a range between “fully open” to“closed”. The feed screw has a preferably adjustable inclination anglerelative to the support body, so that the front end of the support bodyrises from the grain product pile when the feed screw is orientedvertically. The feed screw for the support body has a pitch whichincreases towards the drive unit. The support body includes couplingunits capable of combining several devices to a formation whichincreases the operating range. The support body includes a temperaturesensor for measuring the temperature of the conveyed grain product, withthe temperature sensor being connected with adjustment devices forregulating the transport velocity of the device. The feed screw includesan axial guide channel and radial exit openings, which are connectedwith a facility supplying air or fluid.

Both embodiments of the novel device eliminate the aforementioneddisadvantages of the conventional devices.

Advantageously, the device is supported by the grain product, whichobviates the need for otherwise required connections or supports, whenthe stationery device is used in a drying silo or a storage silo. Thestationery device can then be used regardless of the type of silo, whichbroadens its application. The stationary device supported by the grainproduct also does not require a permanent operator for holding andguiding the device.

The application is further enhanced by configuring the device as amobile device, which can also be used for grain piles stretching over alarge area, for example, piles in a low-rise storage facility for grainproducts. The mobile device is hereby driven by the backpressure fromthe transported grain product in a filling space. This eliminates theneed for mechanical drive unit to advance the device. Advantageously,the filling space of the mobile device can be easily closed off, so thatthe mobile device can also be used in a stationary operation. This alsoexpands the application for the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Two particular embodiments of the invention will now be described withreference to the drawings, which show in:

FIG. 1 a side view of a stationery device with a support body which isopen at the top,

FIG. 2 a top view of the device of FIG. 1,

FIG. 3 a side view of the stationery device with a support body which isopen at the bottom,

FIG. 4 a side view of the stationery device with a closed, hollowsupport body,

FIG. 5 a side view of the stationery device with a plate-shaped supportbody,

FIG. 6 a side view of a mobile device,

FIG. 7 a different side view of the mobile device,

FIG. 8 a top view of the mobile device, and

FIG. 9 a side view of the mobile device with a special feed screw.

DETAILED DESCRIPTION OF THE INVENTION

The stationery device for circulating a grain product according to FIGS.1 to 5 includes essentially a feed screw 1 and a drive unit 2 for thefeed screw 1. The feed screw 1 and the drive unit 2 are releasablycoupled with one another by a coupling unit 3, so that a feed screw 1with a selected length can be used in accordance with the application.The feed screw 1 includes preferably an inner guide channel 4 withradial exit openings 5, which are connected by a supply hose 6 with asupply unit 7 for supplying air or a fluid. The drive unit 2 ispreferably electrically operated and is rigidly connected with a supportbody 9 by mounting elements 8.

As illustrated in FIGS. 1 and 2, the support body 9 is cup-shaped andincludes a bottom plate 10 and a circumferential wall 11. The bottomplate can be round, polygonal or have an aerodynamic shape. Thecup-shaped support body 9 is open at the top. The bottom plate 10 isoriented perpendicular to the axis of the feed screw 1 and has a sizematched to the feed capacity of the feed screw 1. The size of the bottomplate 10 is selected, so that a supporting force of the support body 9maintains the device on the surface of the grain product. Because theopen side of the cup-shaped support body faces up, the drive unit 2 isinserted in the support body 9 and secured to the bottom plate 10.

The bottom plate 10 also includes a blocking plate 12, which is arrangedparallel to the axis of the feed screw 1 and oriented in the radialdirection with respect to the axis of the feed screw 1. The area ofblocking plate 12 is matched to the magnitude of the torque exerted bythe feed screw 1. The blocking plate 12 is preferably height-adjustableand arranged in the bottom plate 10 so as to be lockable in differentpositions. In this way, the blocking plate 12 can be adjusted to matchthe application-specific magnitude of the torque at the feed screw 1.

FIG. 3 shows an identical device with a likewise cup-shaped support body9 which, however, is open towards the bottom. The blocking plate 12 ishereby also displaceable and lockable.

FIG. 4 shows the device for circulating a grain product, which alsoincludes a feed screw 1, a drive unit 2 and a support body 9, wherebythe support body 9 is implemented as a sealed, hollow body. The airtrapped inside the hollow body creates additional buoyancy, so that thesupport body can have a smaller diameter. The blocking plate 12 isrigidly connected, preferably welded, to the bottom side of the hollowsupport body 9.

FIG. 5 shows a plate-shaped support body 9 of the device for circulatinga grain product, with the blocking plate 12 again being welded to thebottom side.

The operation of the stationary embodiments of the device forcirculating a grain product is relatively simple and can therefore beeasily identified from the diagrams of FIGS. 1 to 5.

The feed screw 1 of the device is placed horizontally on the grainproduct, with the free end of the feed screw 1 contacting the grainproduct. The drive unit 2 is then switched on, so that the feed screw 1digs into the grain product and attempts to orient itself in thevertical direction. The digging process ends when the entire surfacearea of the support body 9 rests on the grain product. The grain productis then transported by pushing the grain product located in the threadsof the feed screw 1 upward and depositing it on the surface of the grainproduct. Only the lowest turns receive new grain, because the upperthreads do not have any available space to receive additional grain. Thegrain at the lowest level is therefore always transported to thesurface, while the intermediate layers settle into the lower, freed-upcavities. Removal of the grain from the bottom and depositing it at thetop, and settling of the grain that is not transported creates acirculation within the deposited grain product, which moves warmer grainlayers to the top and cooler grain layers to the bottom. Because thedevice is not subjected to radial forces, the device remains stationaryduring operation. The device also remains at its resting position,because the peripheral forces produced by the rotary motion of the feedscrew 1 are absorbed by the blocking plate 12 immersed in the grainproduct. Stated in differently, only the feed screw 1 rotates, whereasin the device remains stationery.

The mobile device for circulating a grain product according to FIGS. 6to 9 is particularly suited for a low-rise storage building and includesa bottom support plate 13 and a feed screw 1′ which has already beendescribed with reference to the first embodiment. The feed screw 1′extends through the center of the bottom support plate 13 and isoriented either perpendicular to the support plate 13 or is inclinedwith respect to the support plate 13, so that the front section of thesupport plate 13 rises when the feed screw 1′ attempts to assume avertical orientation. The inclination angle of the bottom support plate13 can be adjustable.

The bottom support plate 13 has a circular surface with an opentrapezoidal area segment. A filling space 14 is formed above the openarea segment of the bottom support plate 13. The filling space 14 isprism-shaped, matching the open trapezoidal area segment of the bottomsupport plate 13. The filling space 14 is bounded by a front wall 15,two sidewalls 16, 16′ and a cover-side support plate 17. The front wall15 and the sidewalls 16, 16′ are oriented perpendicular on the bottomsupport plate 13, while the cover-side support plate 17 is orientedparallel to the bottom support plate 13. The filling space 14 forms adischarge region 18 which faces the front wall 15, is covered by thecover-side support plate 17, and is bounded by the sidewalls 16, 16′,and which opens into the horizontal direction. The sidewalls 16, 16′ areconstructed to rotate about a vertical rotation axis on the side thatfaces the discharge region 18 and faces away from the front wall 15.This divides the sidewalls 16, 16′ into a stationary and a pivotableregion 19, 19′. When the pivotable regions 19, 19′ of the sidewalls 16,16′ are oriented towards each other, they open up a very small dischargeregion 18. Conversely, when the pivotable regions 19, 19′ are orientedaway from each other, they open up a discharge region 18 with a maximumopening. One or both pivotable regions 19, 19′ can be designed so as toclose off the filling space 14. This prevents the grain products frombeing discharged and the device from moving while the grain iscirculated. An additional support plate 20, 20′ is disposed horizontallyand directly above the bottom support plate 13 and is secured on thepivotable regions 19, 19′ of the sidewalls 16, 16′. The additionalsupport plate 20, 20′ is shaped and sized so as to close off the bottomof the filling space 14, as soon as the pivotable region 19, 19′ of thesidewalls 16, 16′ are rotated against each other, thereby reducing orclosing the filling space 14 and the discharge region 18. Both the openarea segment in the bottom support plate 13 and the cover-side supportplate 17 are sized to match the maximum fill volume.

Those of skill in the art will recognize that the bottom support plate13 and the cover-side support plate 17 can be designed according to theexemplary support body 9 of the stationery device, and that the fillingspace required for the drive can be integrated therein. One side of thebottom support plate 13 also includes a stand-up guide plate 21. Theguide plate 21 is oriented parallel to the operating direction of thedevice. The size and orientation of the guide plate 21 are designed forsupport by a piled-up dam of the grain product. The size, shape andangle of the guide plate 21 are matched accordingly. Those of skill inthe art may want to add one or more additional guide plates 21.

Two height-adjustable blocking plates 22, 22′ extend through the bottomsupport plate 13. These are each mounted on the side outside the fillingspace 14 and are sized and shaped to prevent the device from rotating.The height of the blocking plates 22, 22′ can be adjusted independent ofeach other by hand or automatically by a motor, based on certainparameters. A rear steering unit 23, which is immersed in the grainproduct and can pivot about a vertical rotation axis, is attached to thecover-side support plate 17 inside the filling space 14, separating thedischarge region 18 in the center. The effective area of the rearsteering unit 23 is matched to the steering characteristic of thedevice. A front steering unit 24, which is also immersed in the grainproduct and can also rotate about a vertical rotation axis, is securedbelow the bottom support plate 13 on the same line as the rear steeringunit 23, facing the rear steering unit 23. The effective areas of thefront steering unit 24 and the rear steering unit 23 are approximatelyidentical. Both the front steering unit 24 and the rear steering unit 23are used to steer the device in a desired direction and can be adjustedindependent from each other, either manually or automatically with amotor, based on certain parameters. Using blocking plates 22, 22′ and/orthe rear steering unit 23 and/or the front steering unit 24 is optional.

The feed screw 1′ is non-rotatably connected with the drive unit 2′,whereby the drive unit 2′ is attached to the cover-side support plate 17by a seat 25. The drive unit 2′ can be powered by electric energy or canbe implemented as an internal combustion engine. The rotation speed onthe driven side is approximately 250 to 750 min⁻¹.

The feed screw 1′ is conventional and has a screw diameter ofapproximately 50 to 100 mm. The diameter and the pitch of the feed screw1′ as well as the rotation speed of the feed screw 1′ can be matched tothe quantity of the transported grain. The length of the feed screw 1′is also variable and is approximately between 1,000 and 4,000 mm long,with the lower end immersed in a grain pile.

Like the stationery device depicted in FIGS. 1 to 5, the feed screw 1′can be again be implemented as a hollow shaft which is connected withthe supply unit 7 for supplying air or a fluid.

As shown in FIG. 6, the feed screw 1′ can include an eccentricallysecured weight in the region of the filling space 14, whereby therotation speed of the feed screw 1′ generates additional translatoryimpulses. A corresponding unbalanced mass 28 can be secured on the feedscrew 1′ so that of the translatory impulses operate perpendicular toboth the front wall 15 and the discharge region 18.

FIG. 9 shows a feed screw 1′ with a pitch which increases steadilytowards the drive side. As a result, the different transport spacesformed between the tooth profiles increase in size toward the drive unit2′. The grain is then not only received from the lower regions, but fromall the layers of the grain pile surrounding the feed screw 1′. Removingthe grain product over the entire length of the feed screw 1′ reducesthe lateral resistance applied to the feed screw 1′ by the grainproduct. This makes it easier for the feed screw 1′ to move through thegrain product. In the region of the cover-side support plate 17, thedevice is preferably provided with lateral, front and rear couplingunits 26, which can be used to couple several mobile devices togethervia corresponding spacers. A formation of several devices can then beassembled for covering a larger area of the grain product. Suchformation can consist, for example, of two or more rows of optionallyinterleaved devices arranged side-by-side. The formation can be steeredin a different direction, so that the transport capacity of the feedscrew 1′ and hence the drive speed of one or several devices located onthe outside can be switched off or reduced, so that the devices whichare switched-off or throttled down become the rotation axis for theentire formation of the devices.

The rear area of the mobile devices can also include a temperaturesensor 27 for measuring a temperature of the discharged grain productand determining the drive speed of the device using suitable controlelements. If the transported grain product has a higher temperature,then the drive speed is reduced. Conversely, if the temperature of thetransported grain product is lower, then the drive speed is increased.In this way, local hotspots can be treated more effectively.

In the following, a discontinuous operation of the mobile devices in alow-rise storage building for attempting to eliminate a hotspot will bedescribed. The device is here moved across the surface of the grainproduct to a previously identified location of a hotspot which islocated about 1 to 2 m below the surface. Advantageously, the device andthe feed screw 1′ can be transported separately which may be necessarydue to their length. The upper end of the feed screw 1′ is non-rotatablyconnected with the driven side of the drive unit 2′ and placed flat ontothe grain product. The drive unit 2′ is then switched on, and the feedscrew 1′ automatically digs into the grain product, changing itsorientation from horizontal to vertical. The feed screw 1′ transportsgrain product into the filling space 14 commensurate with its rotationspeed, its diameter, and its pitch. After the filling space 14 is filledto maximum capacity, a corresponding fill pressure is produced which isconfined by the front wall 15 and the sidewalls 16, 16′ and is releasedtoward the discharge region 18. The additional feed pushes the grainproduct out of the discharge region 18. The flow of the grain productfrom the filling space 14 towards the discharge region 18 also producesa backpressure, which pushes on the front wall of the filling space 14and moves the entire device in an operating direction. The device whichis positioned on the grain product, then moves in the operatingdirection, pushing the grain product which had been moved out of theregion of the hotspot out of the filling space 14 and placing it on thegrain dam. The length of the feed screw 1′ and the drive unit 2′ causepulsed vibrations in the device which advance the device in theoperating direction. The movement direction of the device can not onlybe controlled by the steering units 23 and 24; instead, an operator mayalso push or rotate the device in one direction or another.

The mobile device can also be used in continuous operation in a low-risestorage building filled with a grain product for mixing the grainproduct during the drying process. An operator hereby orients the devicein a first pass, so that the discharged grain product produces astraight dam in the center of the storage area. The device is thenoriented so that its guide plate 21 contacts the built-up dam. Insubsequent passes, the device is then supported on the accumulatinggrain dam by the guide plate 21, using the torque acting in thedirection of the guide plate 21, and is thereby guided along thebuilt-up dam. An operator reverses the direction of the device at theend of each pass. In this way, the entire area of the low-rise storagebuilding can be treated.

The continuous operation of the mobile device can also be performedautomatically. The device can be equipped with suitable transmitters,sensors and actuators and can be connected to a suitable data processingmachine. The device periodically sends its actual spatial coordinates xand y, and optionally also z, to the data processing machine whichprocesses the coordinates using a suitable program. The data processingmachine in turn transmits to the device parameters for controlling, forexample, the blocking plates 22, 22′, the rear steering unit 23 and/orthe front steering units 24. The automatic operation of the deviceaccording to the invention can be optimized by detecting a hotspot inthe grain pile with suitable installed sensors, which transmit the x, y,and z coordinates of the hotspot to the data processing machine. Thedata processing machine then guides the devices across the low-risestorage facility to the hotspot. The sensors for measuring hotspots canbe temperature sensors, density sensors, oxygen sensors or carbondioxide sensors.

LIST OF REFERENCE SYMBOLS

-   1 feed screw-   2 drive unit-   3 coupling unit-   4 guide channel-   5 radial exit opening-   6 supply hose-   7 supply unit for supplying air or fluid-   8 mounting element-   9 support body-   10 bottom plate-   11 wall-   12 blocking plate-   13 bottom support plate-   14 filling space-   15 front wall-   16 sidewall-   17 cover-side support plate-   18 discharge region of the filling space-   19 rotatable region of the sidewall-   20 additional support of the rotatable region of the sidewall-   21 guide plate-   22 blocking plate-   23 rear steering unit-   24 front steering unit-   25 seat for the drive unit-   26 coupling unit-   27 temperature sensor-   28 unbalanced mass

1. A device for circulating a grain product from a lower to an upperstorage region, comprising: a feed screw having a screw axis andconfigured for immersion in the grain product, and a drive unit drivingthe feed screw, both of which are connected via a coupling unit, whereinthe drive unit is non-rotatably connected with a support body which hasa lower support surface that is inclined relative to the axis of thefeed screw, the support body having a surface area capable of supportingthe device on the surface of the grain product during operation of thefeed screw and including at least one blocking plate oriented parallelto the screw axis and extending in a radial direction with respect tothe screw axis, said blocking plate immersed in the grain product,wherein the blocking plate has a surface area capable of withstandingthe peripheral forces of the rotating feed screw, wherein the feed screwhas a length greater than an immersion depth of the blocking plate, andwherein the feed screw is sized so as to enable the grain product to becirculated from a lowermost to an uppermost storage region.
 2. Thedevice according to claim 1, wherein the support body is cup-shaped witha support surface of arbitrary shape and has an open side facing awayfrom the feed screw.
 3. The device according to claim 1, wherein thesupport body is cup-shaped with a support surface of arbitrary shape andhas an open side facing the feed screw.
 4. The device according to claim1, wherein the support body is provided with a filling space forconveyed grain product and the filling space includes a lateraldischarge region for depositing the conveyed grain product onto a grainpile, wherein the dimensions of the filling space and the dimensions ofthe discharge region are matched to one another, so that a pressuresufficient to move the drive is generated inside the filling space bythe conveyed grain product and applied to the device.
 5. The deviceaccording to claim 4, wherein for regulating the drive velocity of thedevice, the filling space includes near its discharge region anadjusting device, which adjusts a cross-section of an opening of thedischarge region in a range between “fully open” to “closed”.
 6. Thedevice according to claim 4, wherein the feed screw has a preferablyadjustable inclination angle relative to the support body, so that thefront end of the support body rises from the grain product pile when thefeed screw is oriented vertically.
 7. The device according to claim 4,wherein the feed screw for the support body has a pitch which increasestowards the drive unit.
 8. The device according to claim 4, wherein thesupport body includes coupling units combining several devices to aformation which increases an operating range.
 9. The device according toclaim 4, wherein the support body includes a temperature sensor formeasuring the temperature of the conveyed grain product, with thetemperature sensor being connected with adjustment devices forregulating a velocity with which the device moves.
 10. The deviceaccording to claim 1, wherein the feed screw includes an axial guidechannel and radial exit openings, which are connected with a facilitysupplying air or fluid.
 11. The device according to claim 1, wherein theblocking plate is height-adjustable in relation to the bottom plate ofthe support body.
 12. The device according to claim 1, wherein theblocking plate is lockable in different height positions.